C11‐BODIPY581/591 is a fluorescent probe that has been successfully used to evaluate lipid peroxidation in different species, but it has not been completely studied in the dog. Thus, the aim of the present study was to assess lipid peroxidation of dog spermatozoa using C11‐BODIPY581/591 and compare different positive controls of the technique. Twenty‐four ejaculates were collected from 8 adult male dogs. Routine seminal characteristics were evaluated in raw semen. Lipid peroxidation evaluation was performed as described in other species. Samples were divided in three aliquots, exposed to UV radiation, incubated with hydrogen peroxide or left without treatment (control). Lipid peroxidation was significantly greater only in UV‐exposed samples than in the control ones (91 ± 6% vs. 8.3 ± 3.5%, p ˂ .01). In conclusion, C11‐BODIPY581/591 is useful to evaluate lipid peroxidation of dog spermatozoa and UV radiation is a good promoter of membrane oxidation, so irradiated samples can be used as a positive control of this technique.

Chromatin damage is an inclusive term that accounts for any defects in DNA structure, such as DNA single or double-strand breaks, base deletion or modification, DNA inter-strand or intra-strand cross-linkage and protamine deficiency and/or mispackage (Esteves et al., 2020). It may occur during spermatogenesis, spermiogenesis, epididymal transit or post-ejaculation (Esteves et al., 2020).However, assessment of DNA structure is not usually included in routine semen analysis despite DNA status is associated with embryo development and pregnancy rates, being a better marker of fertility than conventional semen parameters (Evenson, 2016;Vernocchi et al., 2014).Techniques to evaluate chromatin damage can be divided into two main groups: (1) Sperm DNA fragmentation tests such as TUNEL (terminal dUTP nick-end labelling), ISNT (in situ nick translation assay), SCSA (sperm chromatin structure assay), SCD (sperm chromatin dispersion assay) and Comet assay; and (2) Sperm chromatin